Engineering Mechanical Engineering or......Maths?

[masterred]

I'm currently a rising sophomore in college on track for engineering. I have to say, I love solving math problems, especially Calculus. I love Calculus.
I started to take physics classes and I started to lose interest, mainly because its difficult and requires a lot of extra time to study, time I sometimes don't have. I've always been fascinated with trains and train systems. I love the uniformity and how amazingly fast they can go, but I've always been interested in the wheels and how they turn and how they behave during emergency breaking at high speeds. What engineering field would cover designing and testing new trains?

 

[ModusPwnd]

I think trains have many systems and subsystems that span the breadth of engineering. I would guess that designing a train requires electrical, mechanical, computer, chemical and civil engineering skill. Teams of people working on different components.